The invention relates to a dental furnace, and more particularly to a dental furnace having an effective firing base.
DE 26 32 846 and U.S. Pat. No. 4,139,341, which is hereby incorporated by reference, disclose a dental furnace in which a hood-shaped firing chamber comprises a bottom that is configured as a base for the material being fired. The base for the material being fired is approximately arranged at the same level as the surrounding areas, thus substantially simplifying the handling.
Dental furnaces of this kind have stood the test of decades.
A similar dental furnace for example is known from DE 199 05 666 and U.S. Pat. No. 6,252,202 which is hereby incorporated by reference. This dental furnace also comprises a hood-shaped firing chamber that may be moved vertically relative to a firing platform. The firing platform is supported on an insulation plate and is designed to receive the dental restoration part by means of a recess.
For the burning of dental ceramics it is very important that a precise temperature profile is complied with during the burning or firing process. A temperature profile of this kind is ensured by controlled heating via one or more heating coils, wherein one temperature sensor or more temperature sensors are destined for controlling the interior temperature of the firing chamber. For financial reasons it is desirable to limit the number of temperature sensors, in particular in the case of vacuum dental firing furnaces as the passageways always must be sealed in a particular manner.
Typically, the dental restoration parts are centrally arranged in the firing chamber. Often, however, the insertion does not exactly take place in the center, or several dental restoration parts are burned or fired at the same time in order to considerably increase the efficiency of the firing process in this manner.
To ensure a given and uniform temperature in the firing furnace though, it is frequent practice to produce the receiving section for the dental restoration parts, e.g. the base for the material being fired, according to above-mentioned DE 26 32 846 with a good thermal conductivity and solid design, as it is also provided for example in the firing furnace according to DE 195 42 984 and U.S. Pat. No. 5,788,485, which is hereby incorporated by reference.
In order to shorten the firing cycle it has become known to accelerate the cooling down by means of opening the hood of the dental furnace. In this way, a temperature gradient is frequently generated in the receiving section, which may also result in the breakage of the receiving section.